JPH04344107A - Switchgear - Google Patents

Abstract

PURPOSE:To provide a switchgear, by which grounding of a main circuit, the measurements of main circuit resistances, and the withstand voltage test of a cable, etc., are performed simply without any grounding switch and moreover without taking off a cable connector from it. CONSTITUTION:In a switchgear, provided are a sealed container 3 wherein a main circuit charging part comprising a breaker 6 and disconnectors 5, 7, etc., is housed, a cable bushing 8 provided on the sidewall surface of the sealed container 3 which penctrates through the sidewall and is in connection with the main circuit charging part, a T-shaped cable connector 24 whose one side part is in connection with the cable bushing 8, and a charging bushing 39 which is connected removably with the other side part of the T-shaped cable connector 24 in the cases of a withstand voltage test, grounding of the main circuit, and the measurements of main circuit resistances, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to switchgears such as gas-insulated switchgears, air-insulated switchgears, and solid-insulated switchgears, and particularly relates to improvements in the lead-in and pull-out portions of external cables.

0002

2. Description of the Related Art Conventionally, a gas-insulated switchgear constituting a power distribution board as shown in FIG. 5, for example, has a structure as shown in FIG. 6.

That is, a frame 2 is placed on a foundation base 1 on the floor.
A vertically long airtight container 3 is installed through the container 3, and on the front plate of this container 3, a busbar bushing 4, a power-side disconnector 5, a gas circuit breaker 6, a load-side disconnector 7, and a cable bushing 8 are installed in order from the top.
are installed airtightly through each main circuit, and the main circuit live parts are housed in the container 3, and the terminals of each main circuit device are connected with conductors in the container 3 to form a main circuit. is filled with an insulating gas such as SF6 gas.

Then, the molded busbar 9 from the adjacent panel is removably connected to the busbar bushing 4 from the front of the container 3, and the cable 11 laid in the cable pit 10 on the floor is raised to form an L-shape at its tip. cable connector 1
2 is detachably connected to the cable bushing 8 from the front of the container 3.

Note that 13 and 14 are disconnectors 5 and 7, respectively.
and 15 are the operating devices for the circuit breaker 6, and these operating devices 13 to 15 are arranged on the front surface of the container 3. 16 is a front door, 17 is a cable bracket, and 18 is a ground bus bar.

By the way, in the above-mentioned switchgear, when the main circuit is grounded during equipment inspection work, as shown in FIG. 7, open the front door 16, remove the cable bracket 17, and connect the cable connector 12. After removing it from the cable bushing 8 and holding it with a fixing metal fitting 19 prepared separately, connect the internal conductor of the cable bushing 8 to the ground bus bar 18 using an electric wire 20 with a clip.
I am trying to connect to.

[0007] Furthermore, when measuring the contact resistance of the main circuit,
As described above, this is done by removing the cable connector 12 and measuring the resistance between the internal conductor of the cable bushing 8 and the internal conductor of the cable bushing in the adjacent panel connected by the bus bar 9.

Furthermore, the voltage resistance test of the cable 11 was performed as shown in FIG.
As shown by the two-dot chain line in , this test is carried out by applying a voltage from the test power source 21 to the terminal conductor of the cable connector 12 while holding the removed cable connector 12 with the fixing fitting 19.

On the other hand, conventionally, there is a switchgear in which a line-side earthing switch 22 is connected between a load-side disconnector 7 and a cable bushing 12, as shown by the two-dot chain line in FIG. The configuration is shown in .

That is, in FIG. 8, the same reference numerals as above indicate the same or equivalent parts, and a grounding switch 22 whose one end is connected to the terminal conductor of the cable bushing 8 is installed at the bottom of the container 3, and the grounding switch 22 is connected to the terminal conductor of the cable bushing 8. The other end of the container 22 is led out of the container 3 in an airtight manner, and the other end is connected to the ground bus 18 via a ground wire 23. Note that the operating device for the earthing switch 22 is arranged in parallel with the operating device 14 for the disconnecting switch 7.

In the case of this switchgear, the grounding of the main circuit is achieved by turning on the grounding switch 22, and the contact resistance of the main circuit is measured by connecting the grounding wire 22.
3, turn on the earthing switch 22, and measure the resistance between its external terminal and the external terminal of the earthing switch on the adjacent panel.

Furthermore, the cable withstand voltage test can be carried out by opening the load-side disconnector 7, closing the earthing switch 22, and applying a test voltage from the external terminal of the earthing switch 22.

[0013]

[Problems to be Solved by the Invention] In the conventional switchgear described above, in the case of the one shown in FIGS. 6 and 7,
It is necessary to remove the cable connector 12 together with the cable bracket 17 each time the main circuit is grounded, the main circuit resistance is measured, and the cable withstand voltage test is performed. The problem is that it is necessary to

In particular, when removing the cable connector 12, it is necessary to bend the cable 11 raised from the cable pit 10 forward, but unless the diameter of the cable 11 is very small, it will not bend easily, so it is not normally used. In some cases, the cable connector 12 cannot be removed in the pit 10 of such depth.

[0015] This causes a problem that requires measures such as increasing the pit size and setting an upper limit on the cable size of the cable 11.

In addition, in the case shown in FIG. 8, operations such as main circuit grounding, main circuit resistance measurement, cable withstand voltage test, etc. can be performed more easily by operating the earthing switch 22, but the container 3 Since the earthing switch 22 is housed inside the container 3, it is necessary to increase the size of the container 3, resulting in an increase in the size and cost of the switchgear as a whole.

[0017] The present invention has been made in consideration of the problems of the prior art, and its purpose is to provide a grounding system without providing a grounding switch and without removing the cable connector. The purpose of the present invention is to provide a switchgear that can easily perform main circuit grounding, main circuit resistance measurement, cable withstand voltage tests, etc.

[0018]

[Means for Solving the Problems] In order to achieve the above object, the switchgear of the present invention includes a container housing a main circuit live part of an electrical device such as a circuit breaker or a disconnector, and a wall surface of the container. A cable bushing installed through the main circuit and connected to the live part of the main circuit, a T-shaped cable connector with one side connected to the cable bushing, and a T-shaped cable connector with one side connected to the cable bushing. It is equipped with a energizing bushing that is detachably connected during measurement, etc.

[0019]

[Function] In the switchgear having the above-mentioned configuration, when the energizing bushing is connected to the other side of the T-shaped cable connector whose one side is connected to the cable bushing, the energizing bushing is connected to the cable connector via the cable connector. Connected with cable and cable bushing.

[0020] Therefore, by connecting this energizing bushing to a grounding device, it is possible to ground the main circuit live part, and also the main circuit resistance can be measured using this energizing bushing. A cable withstand voltage test can be performed by opening the disconnector that makes up the circuit and applying a test voltage from the energizing bushing.

[0021]

[Embodiment] An embodiment will be explained using FIGS. 1 to 4. This embodiment shows the case of a gas insulated switchgear applied to a power distribution lineboard in which disconnectors 5 and 7 are connected to the power supply side and the load side of a gas circuit breaker 6, respectively, as shown in FIG. The same reference numerals indicate the same or equivalent parts, and the difference from the conventional one is that a T-shaped cable connector 24 is provided at the tip of the cable 11 to be connected to the cable bushing 8.

This T-shaped cable connector 24 has a structure as shown in FIG.
Insert the sleeve 26 fixed to the conductor 1 and insert the insulating tube 25
The cable bushing 8 penetrating the sealed container 3 is fitted into the opening on one side, and the stud 28 protruding from the internal conductor 27 of the cable bushing 8 is inserted into the through hole 29 in the upper part of the sleeve 26. A nut 30 is inserted into the stud 28 led out from the sleeve 26 from the opening on the other side of the insulating tube 25.
is tightened to connect the cable connector 24 to the cable bushing 8 and simultaneously connect the two together.

Normally, an insulating plug 31 is fitted into the other side of the insulating tube 25, and the insulating plug 31 is fixed by screwing the stud 28 into a screw hole of a metal fitting 32 embedded in the insulating plug 31. , furthermore, a conductive cap 3 is placed on the outside of this
3 is attached to the embedded nut 34 of the insulating plug 31 by tightening the bolt 35, so that the entire exterior of the cable connector 24 becomes a ground layer.

Note that 36 is a voltage detection terminal for detecting whether or not the main circuit is energized using a voltage detector (not shown), and is normally covered with an insulating cap 37. 38 is insulating tube 2
This tape seals between the lower end opening periphery of No. 5 and the circumferential surface of the cable 11.

On the other hand, when the main circuit is grounded, the main circuit resistance is measured, or the cable withstand voltage test is performed, the cable connector 24
A charging bushing 39 connected to the cable 11 and the main circuit in the container 3 is detachably connected thereto.

As shown in FIG. 3, this charging bushing 39 consists of a bushing body 40 and a through conductor 41.
One end of the bushing body 40 is molded into a shape that can be fitted to the other side of the cable connector 24, and a female thread 42 into which the stud 28 is screwed into one end of the through conductor 41 is provided at the other end for terminal connection. A screw 43 is formed respectively.

For example, when grounding the main circuit for equipment inspection work, open the front door 16, remove the conductive cap 33 and insulating plug 31 from the cable connector 24 in the state shown in FIG. 2, and connect it as shown in FIG. Then, one end of the energizing bushing 39 is fitted into the opening on the other side of the cable connector 24, and the through conductor 41 is connected to the stud 28 and the sleeve 2.
Connect to 6.

Therefore, by grounding the through conductor 41 of the energizing bushing 39 using a grounding wire, the main circuit is grounded without removing the cable connector 24 from the cable bushing 8.

When measuring the main circuit resistance, the energizing bushing 39 is connected to the cable connector 24 in each of the two power distribution boards connected via the busbar 9 in the same manner as described above, and both energizing bushings What is necessary is to measure the resistance between 39 and 39.

Furthermore, in the cable withstand voltage test, as shown by the two-dot chain line in FIG. By leaving the load side disconnector 7 open, the voltage from the test power supply 44 is transferred to the charging bushing 39 and the cable connector 24.
The voltage is applied to the cable 11 through the cable 11, thereby making it possible to perform a voltage resistance test.

In the embodiment, the case of a gas insulated switchgear is shown, but it is obvious that the present invention can be similarly applied to an air insulated switchgear or a solid insulated switchgear.

[0032]

[Effects of the Invention] Since the present invention is constructed as described above, it produces the following effects. A T-type cable connector is connected to the cable bushing penetrated through the wall of the container, and a charging bushing is removably connected to it without removing the connector to conduct withstand voltage tests, main circuit grounding, main circuit resistance measurements, etc. Since it is configured to do this, there is no need to remove the cable connector as in the conventional case, which simplifies the work, eliminates the need for a fixing bracket to hold the cable connector, and also eliminates the need to remove the cable connector. There is no need to make the size of the cable pit larger than necessary, and there is no need to limit the cable size.

Furthermore, since there is no need to provide a line-side grounding switch, it is possible to downsize the container and downsize the switchgear as a whole.Moreover, the T-shaped cable connector can be modified from a conventional cable connector. Since it can be commercialized by adding a grounding switch, the cost can be reduced compared to the case where a grounding switch is provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic cutaway side view showing one embodiment of a switchgear according to the present invention.

FIG. 2 is a cutaway side view of a T-shaped cable connector in one embodiment.

FIG. 3 is a cutaway side view when the energizing bushing is connected in one embodiment.

FIG. 4 is a single-line connection diagram of one embodiment.

FIG. 5 is a single-line connection diagram of a conventional switchgear.

FIG. 6 is a schematic cutaway side view of a conventional switchgear.

7 is a schematic cutaway side view of the main circuit in FIG. 6 when it is grounded; FIG.

FIG. 8 is a schematic cutaway side view of another conventional switchgear.

[Explanation of symbols]

3　Airtight container 5, 7 Disconnector 6　Breaker 8 Cable bushing 24 T-type cable connector 39 Charge bushing

Claims (1)

[Claims] Claim 1: A container housing a main circuit live part of an electrical device such as a circuit breaker or a disconnector, a cable bushing penetrating the wall of the container and connected to the main circuit live part, and one side of the container. A T-shaped cable connector connected to the bushing, and a energized bushing detachably connected to the other side of the connector for voltage resistance tests, main circuit grounding, main circuit resistance measurements, etc. Features switch gear.